1. Field of the Invention
The present invention relates to speaker enclosures and, in particular, concerns a seamless speaker enclosure fabricated from lightweight, sound absorbing materials.
2. Description of the Related Art
Speaker enclosures are used in various applications ranging from home entertainment to music concerts. Conventional speaker enclosures are typically constructed from semi-rigid materials, such as plywood, and have a box-like shape. The front side of the speaker enclosure includes a baffle which has several openings in which the diaphragm portion of the speaker is positioned so that sound emanates from the speaker enclosure. A significant drawback of conventional speaker enclosures is weight. For example, large speakers used at music concerts typically require large speaker enclosures. Generally, large speaker enclosures have to support the weight of the large speakers, and consequently, can be very heavy. As a result, the heavier the speaker enclosure, the more difficult it is to move and support.
Another difficulty that results from constructing speaker enclosures from plywood is that these materials often degrade the sound performance of the speaker. In one aspect, most of the sound that is produced by the speaker should emanate outward from the diaphragm of the speaker away from the speaker enclosure. However, plywood has a tendency to vibrate in response to these inwardly travelling errant sound waves. These errant vibrations can result in distortion of the sound produced by the speakers, including a retransmission of resonant sound waves that tend to magnify unwanted frequencies. To reduce these vibrations, sound engineers have often placed materials inside of the speaker enclosure to dampen the errant sound waves and reduce vibrations. However, placing extraneous materials and objects inside the speaker enclosure results in degradation of the sound performance of the speaker.
One way of dealing with the weight and vibration problems is taught in U.S. Pat. No. 5,519,178, the text of which is hereby incorporated by reference in its entirety. The reference teaches forming a plurality of overlapping carbon fiber layers, at least one sound absorbing layer, and a plurality of fiberglass layers in a mold, wherein each layer is separately hand-laid into position. The formed layers are then cured using heat to thereby create a substantially seamless speaker enclosure having some vibration dampening properties. Unfortunately, the proposed labor intensive fabrication processes are expensive and time consuming, which results in high manufacturing costs. Moreover, speaker enclosure production is bottlenecked by the lengthy curing times required by the layers of materials used, thus drastically affecting part throughput, which also increases manufacturing costs.
Another problem associated with U.S. Pat. No. 5,519,178 is that the reference teaches the use of one or more interposed adhesive layers to bond the inner and outer layered materials to the sound absorbing layer. In some circumstances, the adhesive layers can be incompatible with the inner and outer layered materials. Even after curing, the one or more adhesive layers can form discontinuous bonding regions between the layers. Unfortunately, pockets of gaseous molecules may form in non-adhered regions, which may allow errant vibrations to occur during use. If errant vibrations are not properly attenuated or re-transmitted, then the sound absorbing performance of the speaker enclosure is degraded.
In addition, non-adhered regions may also degrade the seamless integrity of the speaker enclosure. When the seamless integrity of the speaker enclosure is compromised, the inner layers, outer layers, and sound absorbing layer can flex in relation to one another as a result of errant sound waves impinging upon the speaker enclosure walls. This can result in a greater vibration of the speaker enclosure and can increase the amount of errant sound waves escaping from the back and sides of the speaker enclosure.
From the foregoing, there currently exists a need for a more economical lightweight speaker enclosure that reduces distortion of sound signals produced by the speakers as a result of errant sound waves emanating from the speaker enclosure. To this end, there is a need for a speaker enclosure that is fabricated from strong lightweight materials that have sound absorbing qualities. Furthermore, an improved speaker enclosure should also comprise seamless structural characteristics so as to reduce unwanted vibrations and improved part throughput by reducing the mold lay-up times and part cure times.